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Stege NM, Eijgenraam TR, Oliveira Nunes Teixeira V, Feringa AM, Schouten EM, Kuster DW, van der Velden J, Wolters AH, Giepmans BN, Makarewich CA, Bassel-Duby R, Olson EN, de Boer RA, Silljé HH. DWORF Extends Life Span in a PLN-R14del Cardiomyopathy Mouse Model by Reducing Abnormal Sarcoplasmic Reticulum Clusters. Circ Res 2023; 133:1006-1021. [PMID: 37955153 PMCID: PMC10699510 DOI: 10.1161/circresaha.123.323304] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND The p.Arg14del variant of the PLN (phospholamban) gene causes cardiomyopathy, leading to severe heart failure. Calcium handling defects and perinuclear PLN aggregation have both been suggested as pathological drivers of this disease. Dwarf open reading frame (DWORF) has been shown to counteract PLN regulatory calcium handling function in the sarco/endoplasmic reticulum (S/ER). Here, we investigated the potential disease-modulating action of DWORF in this cardiomyopathy and its effects on calcium handling and PLN aggregation. METHODS We studied a PLN-R14del mouse model, which develops cardiomyopathy with similar characteristics as human patients, and explored whether cardiac DWORF overexpression could delay cardiac deterioration. To this end, R14Δ/Δ (homozygous PLN-R14del) mice carrying the DWORF transgene (R14Δ/ΔDWORFTg [R14Δ/Δ mice carrying the DWORF transgene]) were used. RESULTS DWORF expression was suppressed in hearts of R14Δ/Δ mice with severe heart failure. Restoration of DWORF expression in R14Δ/Δ mice delayed cardiac fibrosis and heart failure and increased life span >2-fold (from 8 to 18 weeks). DWORF accelerated sarcoplasmic reticulum calcium reuptake and relaxation in isolated cardiomyocytes with wild-type PLN, but in R14Δ/Δ cardiomyocytes, sarcoplasmic reticulum calcium reuptake and relaxation were already enhanced, and no differences were detected between R14Δ/Δ and R14Δ/ΔDWORFTg. Rather, DWORF overexpression delayed the appearance and formation of large pathogenic perinuclear PLN clusters. Careful examination revealed colocalization of sarcoplasmic reticulum markers with these PLN clusters in both R14Δ/Δ mice and human p.Arg14del PLN heart tissue, and hence these previously termed aggregates are comprised of abnormal organized S/ER. This abnormal S/ER organization in PLN-R14del cardiomyopathy contributes to cardiomyocyte cell loss and replacement fibrosis, consequently resulting in cardiac dysfunction. CONCLUSIONS Disorganized S/ER is a major characteristic of PLN-R14del cardiomyopathy in humans and mice and results in cardiomyocyte death. DWORF overexpression delayed PLN-R14del cardiomyopathy progression and extended life span in R14Δ/Δ mice, by reducing abnormal S/ER clusters.
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Affiliation(s)
- Nienke M. Stege
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Tim R. Eijgenraam
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Vivian Oliveira Nunes Teixeira
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Anna M. Feringa
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Elisabeth M. Schouten
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Diederik W.D. Kuster
- Department of Physiology (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
| | - Anouk H.G. Wolters
- Biomedical Sciences of Cells and Systems, UMC Groningen, University of Groningen, the Netherlands (A.H.G.W., B.N.G.G.)
| | - Ben N.G. Giepmans
- Biomedical Sciences of Cells and Systems, UMC Groningen, University of Groningen, the Netherlands (A.H.G.W., B.N.G.G.)
| | - Catherine A. Makarewich
- Division of Molecular Cardiovascular Biology of the Heart Institute, Cincinnati Children’s Hospital Medical Center, OH (C.A.M.)
- Department of Pediatrics, University of Cincinnati College of Medicine, OH (C.A.M.)
| | - Rhonda Bassel-Duby
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas (R.B.-D., E.N.O.)
| | - Eric N. Olson
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas (R.B.-D., E.N.O.)
| | - Rudolf A. de Boer
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands (R.A.d.B.)
| | - Herman H.W. Silljé
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
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Fan X, Yang G, Duru F, Grilli M, Akin I, Zhou X, Saguner AM, Ei-Battrawy I. Arrhythmogenic Cardiomyopathy: from Preclinical Models to Genotype-phenotype Correlation and Pathophysiology. Stem Cell Rev Rep 2023; 19:2683-2708. [PMID: 37731079 PMCID: PMC10661732 DOI: 10.1007/s12015-023-10615-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
Arrhythmogenic cardiomyopathy (ACM) is a hereditary myocardial disease characterized by the replacement of the ventricular myocardium with fibrous fatty deposits. ACM is usually inherited in an autosomal dominant pattern with variable penetrance and expressivity, which is mainly related to ventricular tachyarrhythmia and sudden cardiac death (SCD). Importantly, significant progress has been made in determining the genetic background of ACM due to the development of new techniques for genetic analysis. The exact molecular pathomechanism of ACM, however, is not completely clear and the genotype-phenotype correlations have not been fully elucidated, which are useful to predict the prognosis and treatment of ACM patients. Different gene-targeted and transgenic animal models, human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) models, and heterologous expression systems have been developed. Here, this review aims to summarize preclinical ACM models and platforms promoting our understanding of the pathogenesis of ACM and assess their value in elucidating the ACM genotype-phenotype relationship.
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Affiliation(s)
- Xuehui Fan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention of Cardiovascular Diseases, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- European Center for AngioScience (ECAS), German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/ Mannheim, and Centre for Cardiovascular Acute Medicine Mannheim (ZKAM), Medical Centre Mannheim, Heidelberg University, Partner Site, Heidelberg-Mannheim, Germany
| | - Guoqiang Yang
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Department of Acupuncture and Rehabilitation, the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
- Research Unit of Molecular Imaging Probes, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Firat Duru
- Department of Cardiology, University Heart Centre, University Hospital Zurich, Zurich, Switzerland
| | - Maurizio Grilli
- Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Ibrahim Akin
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- European Center for AngioScience (ECAS), German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/ Mannheim, and Centre for Cardiovascular Acute Medicine Mannheim (ZKAM), Medical Centre Mannheim, Heidelberg University, Partner Site, Heidelberg-Mannheim, Germany
| | - Xiaobo Zhou
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention of Cardiovascular Diseases, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China.
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.
- European Center for AngioScience (ECAS), German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/ Mannheim, and Centre for Cardiovascular Acute Medicine Mannheim (ZKAM), Medical Centre Mannheim, Heidelberg University, Partner Site, Heidelberg-Mannheim, Germany.
- First Department of Medicine, University Medical Centre Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
| | - Ardan Muammer Saguner
- Department of Cardiology, University Heart Centre, University Hospital Zurich, Zurich, Switzerland
| | - Ibrahim Ei-Battrawy
- European Center for AngioScience (ECAS), German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/ Mannheim, and Centre for Cardiovascular Acute Medicine Mannheim (ZKAM), Medical Centre Mannheim, Heidelberg University, Partner Site, Heidelberg-Mannheim, Germany.
- Department of Cardiology and Angiology, Ruhr University, Bochum, Germany; Institute of Physiology, Department of Cellular and Translational Physiology and Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr- University Bochum, Bochum, Germany.
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Cleary SR, Teng ACT, Kongmeneck AD, Fang X, Phillips TA, Cho EE, Kekenes-Huskey P, Gramolini AO, Robia SL. Dilated cardiomyopathy variant R14del increases phospholamban pentamer stability, blunting dynamic regulation of cardiac calcium handling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542463. [PMID: 37292897 PMCID: PMC10245957 DOI: 10.1101/2023.05.26.542463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The sarco(endo)plasmic reticulum Ca 2+ ATPase (SERCA) is a membrane transporter that creates and maintains intracellular Ca 2+ stores. In the heart, SERCA is regulated by an inhibitory interaction with the monomeric form of the transmembrane micropeptide phospholamban (PLB). PLB also forms avid homo-pentamers, and dynamic exchange of PLB between pentamers and the regulatory complex with SERCA is an important determinant of cardiac responsiveness to exercise. Here, we investigated two naturally occurring pathogenic mutations of PLB, a cysteine substitution of arginine 9 (R9C) and an in-frame deletion of arginine 14 (R14del). Both mutations are associated with dilated cardiomyopathy. We previously showed that the R9C mutation causes disulfide crosslinking and hyperstabilization of pentamers. While the pathogenic mechanism of R14del is unclear, we hypothesized that this mutation may also alter PLB homo-oligomerization and disrupt the PLB-SERCA regulatory interaction. SDS-PAGE revealed a significantly increased pentamer:monomer ratio for R14del-PLB when compared to WT-PLB. In addition, we quantified homo-oligomerization and SERCA-binding in live cells using fluorescence resonance energy transfer (FRET) microscopy. R14del-PLB showed an increased affinity for homo-oligomerization and decreased binding affinity for SERCA compared to WT, suggesting that, like R9C, the R14del mutation stabilizes PLB in its pentameric form, decreasing its ability to regulate SERCA. Moreover, the R14del mutation reduces the rate of PLB unbinding from the pentamer after a transient Ca 2+ elevation, limiting the rate of re-binding to SERCA. A computational model predicted that hyperstabilization of PLB pentamers by R14del impairs the ability of cardiac Ca 2+ handling to respond to changing heart rates between rest and exercise. We postulate that impaired responsiveness to physiological stress contributes to arrhythmogenesis in human carriers of the R14del mutation.
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Vafiadaki E, Glijnis PC, Doevendans PA, Kranias EG, Sanoudou D. Phospholamban R14del disease: The past, the present and the future. Front Cardiovasc Med 2023; 10:1162205. [PMID: 37144056 PMCID: PMC10151546 DOI: 10.3389/fcvm.2023.1162205] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/03/2023] [Indexed: 05/06/2023] Open
Abstract
Arrhythmogenic cardiomyopathy affects significant number of patients worldwide and is characterized by life-threatening ventricular arrhythmias and sudden cardiac death. Mutations in multiple genes with diverse functions have been reported to date including phospholamban (PLN), a key regulator of sarcoplasmic reticulum (SR) Ca2+ homeostasis and cardiac contractility. The PLN-R14del variant in specific is recognized as the cause in an increasing number of patients worldwide, and extensive investigations have enabled rapid advances towards the delineation of PLN-R14del disease pathogenesis and discovery of an effective treatment. We provide a critical overview of current knowledge on PLN-R14del disease pathophysiology, including clinical, animal model, cellular and biochemical studies, as well as diverse therapeutic approaches that are being pursued. The milestones achieved in <20 years, since the discovery of the PLN R14del mutation (2006), serve as a paradigm of international scientific collaboration and patient involvement towards finding a cure.
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Affiliation(s)
- Elizabeth Vafiadaki
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
| | - Pieter C. Glijnis
- Stichting Genetische Hartspierziekte PLN, Phospholamban Foundation, Wieringerwerf, Netherlands
| | - Pieter A. Doevendans
- Netherlands Heart Institute, Utrecht, Netherlands
- Department of Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Evangelia G. Kranias
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Despina Sanoudou
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
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5
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Dave J, Raad N, Mittal N, Zhang L, Fargnoli A, Oh JG, Savoia ME, Hansen J, Fava M, Yin X, Theofilatos K, Ceholski D, Kohlbrenner E, Jeong D, Wills L, Nonnenmacher M, Haghighi K, Costa KD, Turnbull IC, Mayr M, Cai CL, Kranias EG, Akar FG, Hajjar RJ, Stillitano F. Gene editing reverses arrhythmia susceptibility in humanized PLN-R14del mice: modelling a European cardiomyopathy with global impact. Cardiovasc Res 2022; 118:3140-3150. [PMID: 35191471 PMCID: PMC9732517 DOI: 10.1093/cvr/cvac021] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 02/18/2022] [Indexed: 12/16/2022] Open
Abstract
AIMS A mutation in the phospholamban (PLN) gene, leading to deletion of Arg14 (R14del), has been associated with malignant arrhythmias and ventricular dilation. Identifying pre-symptomatic carriers with vulnerable myocardium is crucial because arrhythmia can result in sudden cardiac death, especially in young adults with PLN-R14del mutation. This study aimed at assessing the efficiency and efficacy of in vivo genome editing, using CRISPR/Cas9 and a cardiotropic adeno-associated virus-9 (AAV9), in improving cardiac function in young adult mice expressing the human PLN-R14del. METHODS AND RESULTS Humanized mice were generated expressing human wild-type (hPLN-WT) or mutant (hPLN-R14del) PLN in the heterozygous state, mimicking human carriers. Cardiac magnetic resonance imaging at 12 weeks of age showed bi-ventricular dilation and increased stroke volume in mutant vs. WT mice, with no deficit in ejection fraction or cardiac output. Challenge of ex vivo hearts with isoproterenol and rapid pacing unmasked higher propensity for sustained ventricular tachycardia (VT) in hPLN-R14del relative to hPLN-WT. Specifically, the VT threshold was significantly reduced (20.3 ± 1.2 Hz in hPLN-R14del vs. 25.7 ± 1.3 Hz in WT, P < 0.01) reflecting higher arrhythmia burden. To inactivate the R14del allele, mice were tail-vein-injected with AAV9.CRISPR/Cas9/gRNA or AAV9 empty capsid (controls). CRISPR-Cas9 efficiency was evaluated by droplet digital polymerase chain reaction and NGS-based amplicon sequencing. In vivo gene editing significantly reduced end-diastolic and stroke volumes in hPLN-R14del CRISPR-treated mice compared to controls. Susceptibility to VT was also reduced, as the VT threshold was significantly increased relative to controls (30.9 ± 2.3 Hz vs. 21.3 ± 1.5 Hz; P < 0.01). CONCLUSIONS This study is the first to show that disruption of hPLN-R14del allele by AAV9-CRISPR/Cas9 improves cardiac function and reduces VT susceptibility in humanized PLN-R14del mice, offering preclinical evidence for translatable approaches to therapeutically suppress the arrhythmogenic phenotype in human patients with PLN-R14del disease.
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Affiliation(s)
- Jaydev Dave
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nour Raad
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nishka Mittal
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lu Zhang
- Department of Pediatrics, Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anthony Fargnoli
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jae Gyun Oh
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Jens Hansen
- Department of Pharmacological Sciences and Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Marika Fava
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xiaoke Yin
- King’s British Heart Foundation Centre, King’s College London, London, UK
| | | | - Delaine Ceholski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Erik Kohlbrenner
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dongtak Jeong
- Department of Molecular & Life Science, College of Science and Convergence Technology, Hanyang University-ERICA, Ansan-si, South Korea
| | - Lauren Wills
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mathieu Nonnenmacher
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kobra Haghighi
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kevin D Costa
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Irene C Turnbull
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manuel Mayr
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- King’s British Heart Foundation Centre, King’s College London, London, UK
| | - Chen-Leng Cai
- Department of Pediatrics, Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Fadi G Akar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Francesca Stillitano
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Deiman FE, Bomer N, van der Meer P, Grote Beverborg N. Review: Precision Medicine Approaches for Genetic Cardiomyopathy: Targeting Phospholamban R14del. Curr Heart Fail Rep 2022; 19:170-179. [PMID: 35699837 PMCID: PMC9329159 DOI: 10.1007/s11897-022-00558-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW Heart failure is a syndrome with poor prognosis and no curative options for the majority of patients. The standard one-size-fits-all-treatment approach, targeting neurohormonal dysregulations, helps to modulate symptoms of heart failure, but fails to address the cause of the problem. Precision medicine aims to go beyond symptom modulation and targets pathophysiological mechanisms that underlie disease. In this review, an overview of how precision medicine can be approached as a treatment strategy for genetic heart disease will be discussed. PLN R14del, a genetic mutation known to cause cardiomyopathy, will be used as an example to describe the potential and pitfalls of precision medicine. RECENT FINDINGS PLN R14del is characterized by several disease hallmarks including calcium dysregulation, metabolic dysfunction, and protein aggregation. The identification of disease-related biological pathways and the effective targeting using several modalities, including gene silencing and signal transduction modulation, may eventually provide novel treatments for genetic heart disease. We propose a workflow on how to approach precision medicine in heart disease. This workflow focuses on deep phenotyping of patient derived material, including in vitro disease modeling. This will allow identification of therapeutic targets and disease modifiers, to be used for the identification of novel biomarkers and the development of precision medicine approaches for genetic cardiomyopathies.
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Affiliation(s)
- Frederik E Deiman
- Department of Cardiology, University Medical Center Groningen, University of Groningen, UMCG Post-zone AB43, PO Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Nils Bomer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, UMCG Post-zone AB43, PO Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Peter van der Meer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, UMCG Post-zone AB43, PO Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Niels Grote Beverborg
- Department of Cardiology, University Medical Center Groningen, University of Groningen, UMCG Post-zone AB43, PO Box 30.001, 9700 RB, Groningen, The Netherlands.
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Aberrant PLN-R14del Protein Interactions Intensify SERCA2a Inhibition, Driving Impaired Ca2+ Handling and Arrhythmogenesis. Int J Mol Sci 2022; 23:ijms23136947. [PMID: 35805951 PMCID: PMC9266971 DOI: 10.3390/ijms23136947] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 02/01/2023] Open
Abstract
Phospholamban (PLN), a key modulator of Ca2+-homeostasis, inhibits sarcoplasmic reticulum (SR) calcium-ATPase (SERCA2a) and regulates cardiac contractility. The human PLN mutation R14del has been identified in arrhythmogenic cardiomyopathy patients worldwide and is currently extensively investigated. In search of the molecular mechanisms mediating the pathological phenotype, we examined PLN-R14del associations to known PLN-interacting partners. We determined that PLN-R14del interactions to key Ca2+-handling proteins SERCA2a and HS-1-associated protein X-1 (HAX-1) were enhanced, indicating the super-inhibition of SERCA2a’s Ca2+-affinity. Additionally, histidine-rich calcium binding protein (HRC) binding to SERCA2a was increased, suggesting the inhibition of SERCA2a maximal velocity. As phosphorylation relieves the inhibitory effect of PLN on SERCA2a activity, we examined the impact of phosphorylation on the PLN-R14del/SERCA2a interaction. Contrary to PLN-WT, phosphorylation did not affect PLN-R14del binding to SERCA2a, due to a lack of Ser-16 phosphorylation in PLN-R14del. No changes were observed in the subcellular distribution of PLN-R14del or its co-localization to SERCA2a. However, in silico predictions suggest structural perturbations in PLN-R14del that could impact its binding and function. Our findings reveal for the first time that by increased binding to SERCA2a and HAX-1, PLN-R14del acts as an enhanced inhibitor of SERCA2a, causing a cascade of molecular events contributing to impaired Ca2+-homeostasis and arrhythmogenesis. Relieving SERCA2a super-inhibition could offer a promising therapeutic approach for PLN-R14del patients.
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Hulsurkar MM, Lahiri SK, Karch J, Wang MC, Wehrens XH. Targeting calcium-mediated inter-organellar crosstalk in cardiac diseases. Expert Opin Ther Targets 2022; 26:303-317. [PMID: 35426759 PMCID: PMC9081256 DOI: 10.1080/14728222.2022.2067479] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Abnormal calcium signaling between organelles such as the sarcoplasmic reticulum (SR), mitochondria and lysosomes is a key feature of heart diseases. Calcium serves as a secondary messenger mediating inter-organellar crosstalk, essential for maintaining the cardiomyocyte function. AREAS COVERED This article examines the available literature related to calcium channels and transporters involved in inter-organellar calcium signaling. The SR calcium-release channels ryanodine receptor type-2 (RyR2) and inositol 1,4,5-trisphosphate receptor (IP3R), and calcium-transporter SR/ER-ATPase 2a (SERCA2a) are illuminated. The roles of mitochondrial voltage-dependent anion channels (VDAC), the mitochondria Ca2+ uniporter complex (MCUC), and the lysosomal H+/Ca2+ exchanger, two pore channels (TPC), and transient receptor potential mucolipin (TRPML) are discussed. Furthermore, recent studies showing calcium-mediated crosstalk between the SR, mitochondria, and lysosomes as well as how this crosstalk is dysregulated in cardiac diseases are placed under the spotlight. EXPERT OPINION Enhanced SR calcium release via RyR2 and reduced SR reuptake via SERCA2a, increased VDAC and MCUC-mediated calcium uptake into mitochondria, and enhanced lysosomal calcium-release via lysosomal TPC and TRPML may all contribute to aberrant calcium homeostasis causing heart disease. While mechanisms of this crosstalk need to be studied further, interventions targeting these calcium channels or combinations thereof might represent a promising therapeutic strategy.
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Affiliation(s)
- Mohit M. Hulsurkar
- Cardiovascular Research Institute
- Department of Molecular Physiology & Biophysics
| | - Satadru K. Lahiri
- Cardiovascular Research Institute
- Department of Molecular Physiology & Biophysics
| | - Jason Karch
- Cardiovascular Research Institute
- Department of Molecular Physiology & Biophysics
| | - Meng C. Wang
- Cardiovascular Research Institute
- Huffington Center on Aging
- Department of Molecular and Human Genetics
- Howard Hughes Medical Institute
| | - Xander H.T. Wehrens
- Cardiovascular Research Institute
- Department of Molecular Physiology & Biophysics
- Dept. of Medicine (Cardiology)
- Dept. of Neuroscience
- Dept. of Pediatrics (Cardiology)
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Morciano G, Rimessi A, Patergnani S, Vitto VAM, Danese A, Kahsay A, Palumbo L, Bonora M, Wieckowski MR, Giorgi C, Pinton P. Calcium dysregulation in heart diseases: Targeting calcium channels to achieve a correct calcium homeostasis. Pharmacol Res 2022; 177:106119. [PMID: 35131483 DOI: 10.1016/j.phrs.2022.106119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 12/16/2022]
Abstract
Intracellular calcium signaling is a universal language source shared by the most part of biological entities inside cells that, all together, give rise to physiological and functional anatomical units, the organ. Although preferentially recognized as signaling between cell life and death processes, in the heart it assumes additional relevance considered the importance of calcium cycling coupled to ATP consumption in excitation-contraction coupling. The concerted action of a plethora of exchangers, channels and pumps inward and outward calcium fluxes where needed, to convert energy and electric impulses in muscle contraction. All this without realizing it, thousands of times, every day. An improper function of those proteins (i.e., variation in expression, mutations onset, dysregulated channeling, differential protein-protein interactions) being part of this signaling network triggers a short circuit with severe acute and chronic pathological consequences reported as arrhythmias, cardiac remodeling, heart failure, reperfusion injury and cardiomyopathies. By acting with chemical, peptide-based and pharmacological modulators of these players, a correction of calcium homeostasis can be achieved accompanied by an amelioration of clinical symptoms. This review will focus on all those defects in calcium homeostasis which occur in the most common cardiac diseases, including myocardial infarction, arrhythmia, hypertrophy, heart failure and cardiomyopathies. This part will be introduced by the state of the art on the proteins involved in calcium homeostasis in cardiomyocytes and followed by the therapeutic treatments that to date, are able to target them and to revert the pathological phenotype.
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Affiliation(s)
- Giampaolo Morciano
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
| | - Alessandro Rimessi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Simone Patergnani
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Veronica A M Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Alberto Danese
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Asrat Kahsay
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Laura Palumbo
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Massimo Bonora
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism. Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
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10
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Kamel SM, van Opbergen CJM, Koopman CD, Verkerk AO, Boukens BJD, de Jonge B, Onderwater YL, van Alebeek E, Chocron S, Polidoro Pontalti C, Weuring WJ, Vos MA, de Boer TP, van Veen TAB, Bakkers J. Istaroxime treatment ameliorates calcium dysregulation in a zebrafish model of phospholamban R14del cardiomyopathy. Nat Commun 2021; 12:7151. [PMID: 34887420 PMCID: PMC8660846 DOI: 10.1038/s41467-021-27461-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/19/2021] [Indexed: 12/27/2022] Open
Abstract
The heterozygous Phospholamban p.Arg14del mutation is found in patients with dilated or arrhythmogenic cardiomyopathy. This mutation triggers cardiac contractile dysfunction and arrhythmogenesis by affecting intracellular Ca2+ dynamics. Little is known about the physiological processes preceding induced cardiomyopathy, which is characterized by sub-epicardial accumulation of fibrofatty tissue, and a specific drug treatment is currently lacking. Here, we address these issues using a knock-in Phospholamban p.Arg14del zebrafish model. Hearts from adult zebrafish with this mutation display age-related remodeling with sub-epicardial inflammation and fibrosis. Echocardiography reveals contractile variations before overt structural changes occur, which correlates at the cellular level with action potential duration alternans. These functional alterations are preceded by diminished Ca2+ transient amplitudes in embryonic hearts as well as an increase in diastolic Ca2+ level, slower Ca2+ transient decay and longer Ca2+ transients in cells of adult hearts. We find that istaroxime treatment ameliorates the in vivo Ca2+ dysregulation, rescues the cellular action potential duration alternans, while it improves cardiac relaxation. Thus, we present insight into the pathophysiology of Phospholamban p.Arg14del cardiomyopathy.
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Affiliation(s)
- S M Kamel
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands
| | - C J M van Opbergen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - C D Koopman
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - A O Verkerk
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Experimental Cardiology, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - B J D Boukens
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Experimental Cardiology, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - B de Jonge
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Y L Onderwater
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands
| | - E van Alebeek
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands
| | - S Chocron
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands
| | - C Polidoro Pontalti
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - W J Weuring
- Department of Genetics, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - M A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - T P de Boer
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - T A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands.
| | - J Bakkers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands.
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands.
- Department of Pediatric Cardiology, Division of Pediatrics, University Medical Center Utrecht, Utrecht, The Netherlands.
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11
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Eijgenraam TR, Boogerd CJ, Stege NM, Oliveira Nunes Teixeira V, Dokter MM, Schmidt LE, Yin X, Theofilatos K, Mayr M, van der Meer P, van Rooij E, van der Velden J, Silljé HHW, de Boer RA. Protein Aggregation Is an Early Manifestation of Phospholamban p.(Arg14del)-Related Cardiomyopathy: Development of PLN-R14del-Related Cardiomyopathy. Circ Heart Fail 2021; 14:e008532. [PMID: 34587756 PMCID: PMC8589082 DOI: 10.1161/circheartfailure.121.008532] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND The p.(Arg14del) pathogenic variant (R14del) of the PLN (phospholamban) gene is a prevalent cause of cardiomyopathy with heart failure. The exact underlying pathophysiology is unknown, and a suitable therapy is unavailable. We aim to identify molecular perturbations underlying this cardiomyopathy in a clinically relevant PLN-R14del mouse model. METHODS We investigated the progression of cardiomyopathy in PLN-R14Δ/Δ mice using echocardiography, ECG, and histological tissue analysis. RNA sequencing and mass spectrometry were performed on cardiac tissues at 3 (before the onset of disease), 5 (mild cardiomyopathy), and 8 (end stage) weeks of age. Data were compared with cardiac expression levels of mice that underwent myocardial ischemia-reperfusion or myocardial infarction surgery, in an effort to identify alterations that are specific to PLN-R14del-related cardiomyopathy. RESULTS At 3 weeks of age, PLN-R14Δ/Δ mice had normal cardiac function, but from the age of 4 weeks, we observed increased myocardial fibrosis and impaired global longitudinal strain. From 5 weeks onward, ventricular dilatation, decreased contractility, and diminished ECG voltages were observed. PLN protein aggregation was present before onset of functional deficits. Transcriptomics and proteomics revealed differential regulation of processes involved in remodeling, inflammation, and metabolic dysfunction, in part, similar to ischemic heart disease. Altered protein homeostasis pathways were identified exclusively in PLN-R14Δ/Δ mice, even before disease onset, in concert with aggregate formation. CONCLUSIONS We mapped the development of PLN-R14del-related cardiomyopathy and identified alterations in proteostasis and PLN protein aggregation among the first manifestations of this disease, which could possibly be a novel target for therapy.
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Affiliation(s)
- Tim R Eijgenraam
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Cornelis J Boogerd
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, University Medical Center Utrecht (C.J.B., E.v.R.)
| | - Nienke M Stege
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Vivian Oliveira Nunes Teixeira
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Martin M Dokter
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Lukas E Schmidt
- King's British Heart Foundation Centre, King's College London, United Kingdom (L.E.S., X.Y., K.T., M.M.)
| | - Xiaoke Yin
- King's British Heart Foundation Centre, King's College London, United Kingdom (L.E.S., X.Y., K.T., M.M.)
| | - Konstantinos Theofilatos
- King's British Heart Foundation Centre, King's College London, United Kingdom (L.E.S., X.Y., K.T., M.M.)
| | - Manuel Mayr
- King's British Heart Foundation Centre, King's College London, United Kingdom (L.E.S., X.Y., K.T., M.M.)
| | - Peter van der Meer
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Eva van Rooij
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, University Medical Center Utrecht (C.J.B., E.v.R.)
| | - Jolanda van der Velden
- Department of Physiology, Vrije Universiteit, Amsterdam University Medical Center, Amsterdam Cardiovascular Sciences, the Netherlands (J.v.d.V.)
| | - Herman H W Silljé
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
| | - Rudolf A de Boer
- Department of Cardiology, University of Groningen, University Medical Center Groningen, the Netherlands (T.R.E., N.M.S., V.O.N.T., M.M.D., P.v.d.M., H.H.W.S., R.A.d.B.)
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12
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Koch D, Alexandrovich A, Funk F, Kho AL, Schmitt JP, Gautel M. Molecular noise filtering in the β-adrenergic signaling network by phospholamban pentamers. Cell Rep 2021; 36:109448. [PMID: 34320358 PMCID: PMC8333238 DOI: 10.1016/j.celrep.2021.109448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/16/2021] [Accepted: 07/05/2021] [Indexed: 02/07/2023] Open
Abstract
Phospholamban (PLN) is an important regulator of cardiac calcium handling due to its ability to inhibit the calcium ATPase SERCA. β-Adrenergic stimulation reverses SERCA inhibition via PLN phosphorylation and facilitates fast calcium reuptake. PLN also forms pentamers whose physiological significance has remained elusive. Using mathematical modeling combined with biochemical and cell biological experiments, we show that pentamers regulate both the dynamics and steady-state levels of monomer phosphorylation. Substrate competition by pentamers and a feed-forward loop involving inhibitor-1 can delay monomer phosphorylation by protein kinase A (PKA), whereas cooperative pentamer dephosphorylation enables bistable PLN steady-state phosphorylation. Simulations show that phosphorylation delay and bistability act as complementary filters that reduce the effect of random fluctuations in PKA activity, thereby ensuring consistent monomer phosphorylation and SERCA activity despite noisy upstream signals. Preliminary analyses suggest that the PLN mutation R14del could impair noise filtering, offering a new perspective on how this mutation causes cardiac arrhythmias.
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Affiliation(s)
- Daniel Koch
- Randall Centre for Cell and Molecular Biophysics, King's College London, SE1 1UL London, UK.
| | | | - Florian Funk
- Institute of Pharmacology and Clinical Pharmacology, and Cardiovascular Research Institute Düsseldorf (CARID), University Hospital Düsseldorf, 40225 Düsseldorf, Germany
| | - Ay Lin Kho
- Randall Centre for Cell and Molecular Biophysics, King's College London, SE1 1UL London, UK
| | - Joachim P Schmitt
- Institute of Pharmacology and Clinical Pharmacology, and Cardiovascular Research Institute Düsseldorf (CARID), University Hospital Düsseldorf, 40225 Düsseldorf, Germany
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics, King's College London, SE1 1UL London, UK
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13
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Cuello F, Knaust AE, Saleem U, Loos M, Raabe J, Mosqueira D, Laufer S, Schweizer M, van der Kraak P, Flenner F, Ulmer BM, Braren I, Yin X, Theofilatos K, Ruiz‐Orera J, Patone G, Klampe B, Schulze T, Piasecki A, Pinto Y, Vink A, Hübner N, Harding S, Mayr M, Denning C, Eschenhagen T, Hansen A. Impairment of the ER/mitochondria compartment in human cardiomyocytes with PLN p.Arg14del mutation. EMBO Mol Med 2021; 13:e13074. [PMID: 33998164 PMCID: PMC8185541 DOI: 10.15252/emmm.202013074] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 03/31/2021] [Accepted: 04/07/2021] [Indexed: 12/28/2022] Open
Abstract
The phospholamban (PLN) p.Arg14del mutation causes dilated cardiomyopathy, with the molecular disease mechanisms incompletely understood. Patient dermal fibroblasts were reprogrammed to hiPSC, isogenic controls were established by CRISPR/Cas9, and cardiomyocytes were differentiated. Mutant cardiomyocytes revealed significantly prolonged Ca2+ transient decay time, Ca2+ -load dependent irregular beating pattern, and lower force. Proteomic analysis revealed less endoplasmic reticulum (ER) and ribosomal and mitochondrial proteins. Electron microscopy showed dilation of the ER and large lipid droplets in close association with mitochondria. Follow-up experiments confirmed impairment of the ER/mitochondria compartment. PLN p.Arg14del end-stage heart failure samples revealed perinuclear aggregates positive for ER marker proteins and oxidative stress in comparison with ischemic heart failure and non-failing donor heart samples. Transduction of PLN p.Arg14del EHTs with the Ca2+ -binding proteins GCaMP6f or parvalbumin improved the disease phenotype. This study identified impairment of the ER/mitochondria compartment without SR dysfunction as a novel disease mechanism underlying PLN p.Arg14del cardiomyopathy. The pathology was improved by Ca2+ -scavenging, suggesting impaired local Ca2+ cycling as an important disease culprit.
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14
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Impaired Right Ventricular Calcium Cycling Is an Early Risk Factor in R14del-Phospholamban Arrhythmias. J Pers Med 2021; 11:jpm11060502. [PMID: 34204946 PMCID: PMC8226909 DOI: 10.3390/jpm11060502] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/27/2021] [Accepted: 05/30/2021] [Indexed: 12/22/2022] Open
Abstract
The inherited mutation (R14del) in the calcium regulatory protein phospholamban (PLN) is linked to malignant ventricular arrhythmia with poor prognosis starting at adolescence. However, the underlying early mechanisms that may serve as prognostic factors remain elusive. This study generated humanized mice in which the endogenous gene was replaced with either human wild type or R14del-PLN and addressed the early molecular and cellular pathogenic mechanisms. R14del-PLN mice exhibited stress-induced impairment of atrioventricular conduction, and prolongation of both ventricular activation and repolarization times in association with ventricular tachyarrhythmia, originating from the right ventricle (RV). Most of these distinct electrocardiographic features were remarkably similar to those in R14del-PLN patients. Studies in isolated cardiomyocytes revealed RV-specific calcium defects, including prolonged action potential duration, depressed calcium kinetics and contractile parameters, and elevated diastolic Ca-levels. Ca-sparks were also higher although SR Ca-load was reduced. Accordingly, stress conditions induced after contractions, and inclusion of the CaMKII inhibitor KN93 reversed this proarrhythmic parameter. Compensatory responses included altered expression of key genes associated with Ca-cycling. These data suggest that R14del-PLN cardiomyopathy originates with RV-specific impairment of Ca-cycling and point to the urgent need to improve risk stratification in asymptomatic carriers to prevent fatal arrhythmias and delay cardiomyopathy onset.
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15
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Raad N, Bittihn P, Cacheux M, Jeong D, Ilkan Z, Ceholski D, Kohlbrenner E, Zhang L, Cai CL, Kranias EG, Hajjar RJ, Stillitano F, Akar FG. Arrhythmia Mechanism and Dynamics in a Humanized Mouse Model of Inherited Cardiomyopathy Caused by Phospholamban R14del Mutation. Circulation 2021; 144:441-454. [PMID: 34024116 DOI: 10.1161/circulationaha.119.043502] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Arginine (Arg) 14 deletion (R14del) in the calcium regulatory protein phospholamban (hPLNR14del) has been identified as a disease-causing mutation in patients with an inherited cardiomyopathy. Mechanisms underlying the early arrhythmogenic phenotype that predisposes carriers of this mutation to sudden death with no apparent structural remodeling remain unclear. METHODS To address this, we performed high spatiotemporal resolution optical mapping of intact hearts from adult knock-in mice harboring the human PLNWT (wildtype [WT], n=12) or the heterozygous human PLNR14del mutation (R14del, n=12) before and after ex vivo challenge with isoproterenol and rapid pacing. RESULTS Adverse electrophysiological remodeling was evident in the absence of significant structural or hemodynamic changes. R14del hearts exhibited increased arrhythmia susceptibility compared with wildtype. Underlying this susceptibility was preferential right ventricular action potential prolongation that was unresponsive to β-adrenergic stimulation. A steep repolarization gradient at the left ventricular/right ventricular interface provided the substrate for interventricular activation delays and ultimately local conduction block during rapid pacing. This was followed by the initiation of macroreentrant circuits supporting the onset of ventricular tachycardia. Once sustained, these circuits evolved into high-frequency rotors, which in their majority were pinned to the right ventricle. These rotors exhibited unique spatiotemporal dynamics that promoted their increased stability in R14del compared with wildtype hearts. CONCLUSIONS Our findings highlight the crucial role of primary electric remodeling caused by the hPLNR14del mutation. These inherently arrhythmogenic features form the substrate for adrenergic-mediated VT at early stages of PLNR14del induced cardiomyopathy.
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Affiliation(s)
- Nour Raad
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.).,Poliklinik für Innere Medizin I, Rechts der Isar Hospital, Technical University Munich, Germany (N.R.).,German Center for Cardiovascular Research, Munich Heart Alliance (N.R.)
| | - Philip Bittihn
- BioCircuits Institute, University of California, San Diego (P.B.).,Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany (P.B.)
| | - Marine Cacheux
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Dongtak Jeong
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Zeki Ilkan
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Delaine Ceholski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Erik Kohlbrenner
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Lu Zhang
- Indiana University School of Medicine, Indianapolis (L.Z., C.C.)
| | - Chen-Leng Cai
- Indiana University School of Medicine, Indianapolis (L.Z., C.C.)
| | | | - Roger J Hajjar
- Phospholamban Foundation, Middenmeer, The Netherlands (R.J.H.)
| | - Francesca Stillitano
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Fadi G Akar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.).,School of Medicine (F.G.A.), Yale University, New Haven, CT.,Department of Biomedical Engineering (F.G.A.). Yale University, New Haven, CT
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16
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Vilella R, Sgarbi G, Naponelli V, Savi M, Bocchi L, Liuzzi F, Righetti R, Quaini F, Frati C, Bettuzzi S, Solaini G, Stilli D, Rizzi F, Baracca A. Effects of Standardized Green Tea Extract and Its Main Component, EGCG, on Mitochondrial Function and Contractile Performance of Healthy Rat Cardiomyocytes. Nutrients 2020; 12:nu12102949. [PMID: 32993022 PMCID: PMC7600665 DOI: 10.3390/nu12102949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022] Open
Abstract
We recently showed that the long-term in vivo administration of green tea catechin extract (GTE) resulted in hyperdynamic cardiomyocyte contractility. The present study investigates the mechanisms underlying GTE action in comparison to its major component, epigallocatechin-3-gallate (EGCG), given at the equivalent amount that would be in the entirety of GTE. Twenty-six male Wistar rats were given 40 mL/day of a tap water solution with either standardized GTE or pure EGCG for 4 weeks. Cardiomyocytes were then isolated for the study. Cellular bioenergetics was found to be significantly improved in both GTE- and EGCG-fed rats compared to that in controls as shown by measuring the maximal mitochondrial respiration rate and the cellular ATP level. Notably, the improvement of mitochondrial function was associated with increased levels of oxidative phosphorylation complexes, whereas the cellular mitochondrial mass was unchanged. However, only the GTE supplement improved cardiomyocyte mechanics and intracellular calcium dynamics, by lowering the expression of total phospholamban (PLB), which led to an increase of both the phosphorylated-PLB/PLB and the sarco-endoplasmic reticulum calcium ATPase/PLB ratios. Our findings suggest that GTE might be a valuable adjuvant tool for counteracting the occurrence and/or the progression of cardiomyopathies in which mitochondrial dysfunction and alteration of intracellular calcium dynamics constitute early pathogenic factors.
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Affiliation(s)
- Rocchina Vilella
- Department of Chemistry, Life Sciences and Environmental Sustainability (SCVSA), University of Parma, 43124 Parma, Italy; (R.V.); (M.S.); (L.B.); (D.S.)
| | - Gianluca Sgarbi
- Department of Biomedical and Neuromotor Sciences (DIBINEM), Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, 40126 Bologna, Italy; (G.S.); (F.L.); (G.S.)
| | - Valeria Naponelli
- Department of Medicine and Surgery (DIMEC), University of Parma, 43125 Parma, Italy; (V.N.); (F.Q.); (C.F.); (S.B.)
- National Institute of Biostructure and Biosystems (INBB), 00136 Rome, Italy
- Centre for Molecular and Translational Oncology (COMT), University of Parma, 43124 Parma, Italy
| | - Monia Savi
- Department of Chemistry, Life Sciences and Environmental Sustainability (SCVSA), University of Parma, 43124 Parma, Italy; (R.V.); (M.S.); (L.B.); (D.S.)
| | - Leonardo Bocchi
- Department of Chemistry, Life Sciences and Environmental Sustainability (SCVSA), University of Parma, 43124 Parma, Italy; (R.V.); (M.S.); (L.B.); (D.S.)
| | - Francesca Liuzzi
- Department of Biomedical and Neuromotor Sciences (DIBINEM), Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, 40126 Bologna, Italy; (G.S.); (F.L.); (G.S.)
| | - Riccardo Righetti
- CNR Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza” Unit of Bologna, 40136 Bologna, Italy;
| | - Federico Quaini
- Department of Medicine and Surgery (DIMEC), University of Parma, 43125 Parma, Italy; (V.N.); (F.Q.); (C.F.); (S.B.)
| | - Caterina Frati
- Department of Medicine and Surgery (DIMEC), University of Parma, 43125 Parma, Italy; (V.N.); (F.Q.); (C.F.); (S.B.)
| | - Saverio Bettuzzi
- Department of Medicine and Surgery (DIMEC), University of Parma, 43125 Parma, Italy; (V.N.); (F.Q.); (C.F.); (S.B.)
- National Institute of Biostructure and Biosystems (INBB), 00136 Rome, Italy
- Centre for Molecular and Translational Oncology (COMT), University of Parma, 43124 Parma, Italy
| | - Giancarlo Solaini
- Department of Biomedical and Neuromotor Sciences (DIBINEM), Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, 40126 Bologna, Italy; (G.S.); (F.L.); (G.S.)
| | - Donatella Stilli
- Department of Chemistry, Life Sciences and Environmental Sustainability (SCVSA), University of Parma, 43124 Parma, Italy; (R.V.); (M.S.); (L.B.); (D.S.)
| | - Federica Rizzi
- Department of Medicine and Surgery (DIMEC), University of Parma, 43125 Parma, Italy; (V.N.); (F.Q.); (C.F.); (S.B.)
- National Institute of Biostructure and Biosystems (INBB), 00136 Rome, Italy
- Centre for Molecular and Translational Oncology (COMT), University of Parma, 43124 Parma, Italy
- Correspondence: (F.R.); (A.B.); Tel.: +39-0521-033816 (F.R.); +39-051-2091244 (A.B.); Fax: +39-0521-033802 (F.R.); +39-051-2091224 (A.B.)
| | - Alessandra Baracca
- Department of Biomedical and Neuromotor Sciences (DIBINEM), Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, 40126 Bologna, Italy; (G.S.); (F.L.); (G.S.)
- Correspondence: (F.R.); (A.B.); Tel.: +39-0521-033816 (F.R.); +39-051-2091244 (A.B.); Fax: +39-0521-033802 (F.R.); +39-051-2091224 (A.B.)
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17
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Gerull B, Brodehl A. Genetic Animal Models for Arrhythmogenic Cardiomyopathy. Front Physiol 2020; 11:624. [PMID: 32670084 PMCID: PMC7327121 DOI: 10.3389/fphys.2020.00624] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/18/2020] [Indexed: 12/12/2022] Open
Abstract
Arrhythmogenic cardiomyopathy has been clinically defined since the 1980s and causes right or biventricular cardiomyopathy associated with ventricular arrhythmia. Although it is a rare cardiac disease, it is responsible for a significant proportion of sudden cardiac deaths, especially in athletes. The majority of patients with arrhythmogenic cardiomyopathy carry one or more genetic variants in desmosomal genes. In the 1990s, several knockout mouse models of genes encoding for desmosomal proteins involved in cell-cell adhesion revealed for the first time embryonic lethality due to cardiac defects. Influenced by these initial discoveries in mice, arrhythmogenic cardiomyopathy received an increasing interest in human cardiovascular genetics, leading to the discovery of mutations initially in desmosomal genes and later on in more than 25 different genes. Of note, even in the clinic, routine genetic diagnostics are important for risk prediction of patients and their relatives with arrhythmogenic cardiomyopathy. Based on improvements in genetic animal engineering, different transgenic, knock-in, or cardiac-specific knockout animal models for desmosomal and nondesmosomal proteins have been generated, leading to important discoveries in this field. Here, we present an overview about the existing animal models of arrhythmogenic cardiomyopathy with a focus on the underlying pathomechanism and its importance for understanding of this disease. Prospectively, novel mechanistic insights gained from the whole animal, organ, tissue, cellular, and molecular levels will lead to the development of efficient personalized therapies for treatment of arrhythmogenic cardiomyopathy.
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Affiliation(s)
- Brenda Gerull
- Comprehensive Heart Failure Center Wuerzburg, Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.,Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Andreas Brodehl
- Erich and Hanna Klessmann Institute for Cardiovascular Research and Development, Heart and Diabetes Center NRW, University Hospitals of the Ruhr-University of Bochum, Bad Oeynhausen, Germany
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18
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Eijgenraam TR, Boukens BJ, Boogerd CJ, Schouten EM, van de Kolk CWA, Stege NM, Te Rijdt WP, Hoorntje ET, van der Zwaag PA, van Rooij E, van Tintelen JP, van den Berg MP, van der Meer P, van der Velden J, Silljé HHW, de Boer RA. The phospholamban p.(Arg14del) pathogenic variant leads to cardiomyopathy with heart failure and is unreponsive to standard heart failure therapy. Sci Rep 2020; 10:9819. [PMID: 32555305 PMCID: PMC7300032 DOI: 10.1038/s41598-020-66656-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023] Open
Abstract
Phospholamban (PLN) plays a role in cardiomyocyte calcium handling as primary inhibitor of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA). The p.(Arg14del) pathogenic variant in the PLN gene results in a high risk of developing dilated or arrhythmogenic cardiomyopathy with heart failure. There is no established treatment other than standard heart failure therapy or heart transplantation. In this study, we generated a novel mouse model with the PLN-R14del pathogenic variant, performed detailed phenotyping, and tested the efficacy of established heart failure therapies eplerenone or metoprolol. Heterozygous PLN-R14del mice demonstrated increased susceptibility to ex vivo induced arrhythmias, and cardiomyopathy at 18 months of age, which was not accelerated by isoproterenol infusion. Homozygous PLN-R14del mice exhibited an accelerated phenotype including cardiac dilatation, contractile dysfunction, decreased ECG potentials, high susceptibility to ex vivo induced arrhythmias, myocardial fibrosis, PLN protein aggregation, and early mortality. Neither eplerenone nor metoprolol administration improved cardiac function or survival. In conclusion, our novel PLN-R14del mouse model exhibits most features of human disease. Administration of standard heart failure therapy did not rescue the phenotype, underscoring the need for better understanding of the pathophysiology of PLN-R14del-associated cardiomyopathy. This model provides a great opportunity to study the pathophysiology, and to screen for potential therapeutic treatments.
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Affiliation(s)
- Tim R Eijgenraam
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, the Netherlands
- Department of Experimental Cardiology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Cornelis J Boogerd
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Center Utrecht, Utrecht, the Netherlands
| | - E Marloes Schouten
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Cees W A van de Kolk
- Central Animal Facility, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Groningen Small Animal Imaging Facility, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Nienke M Stege
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Wouter P Te Rijdt
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Edgar T Hoorntje
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Netherlands Heart Institute, Utrecht, the Netherlands
| | - Paul A van der Zwaag
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Eva van Rooij
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Center Utrecht, Utrecht, the Netherlands
| | - J Peter van Tintelen
- Department of Genetics, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Maarten P van den Berg
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Peter van der Meer
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Herman H W Silljé
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Rudolf A de Boer
- Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
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19
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Association with SERCA2a directs phospholamban trafficking to sarcoplasmic reticulum from a nuclear envelope pool. J Mol Cell Cardiol 2020; 143:107-119. [DOI: 10.1016/j.yjmcc.2020.04.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/08/2020] [Accepted: 04/23/2020] [Indexed: 11/22/2022]
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20
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Wang S, Mao C, Liu S. Peptides encoded by noncoding genes: challenges and perspectives. Signal Transduct Target Ther 2019; 4:57. [PMID: 31871775 PMCID: PMC6908703 DOI: 10.1038/s41392-019-0092-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/17/2019] [Accepted: 10/27/2019] [Indexed: 01/01/2023] Open
Abstract
In recent years, noncoding gene (NCG) translation events have been frequently discovered. The resultant peptides, as novel findings in the life sciences, perform unexpected functions of increasingly recognized importance in many fundamental biological and pathological processes. The emergence of these novel peptides, in turn, has advanced the field of genomics while indispensably aiding living organisms. The peptides from NCGs serve as important links between extracellular stimuli and intracellular adjustment mechanisms. These peptides are also important entry points for further exploration of the mysteries of life that may trigger a new round of revolutionary biotechnological discoveries. Insights into NCG-derived peptides will assist in understanding the secrets of life and the causes of diseases, and will also open up new paths to the treatment of diseases such as cancer. Here, a critical review is presented on the action modes and biological functions of the peptides encoded by NCGs. The challenges and future trends in searching for and studying NCG peptides are also critically discussed.
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Affiliation(s)
- Shuo Wang
- Changhai Hospital, Shanghai, 200433 China
| | - Chuanbin Mao
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, Institute for Biomedical Engineering, Science and Technology, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019-5300 USA
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21
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Verhagen JMA, van den Born M, van der Linde HC, G J Nikkels P, Verdijk RM, Kivlen MH, van Unen LMA, Baas AF, Ter Heide H, van Osch-Gevers L, Hoogeveen-Westerveld M, Herkert JC, Bertoli-Avella AM, van Slegtenhorst MA, Wessels MW, Verheijen FW, Hassel D, Hofstra RMW, Hegde RS, van Hasselt PM, van Ham TJ, van de Laar IMBH. Biallelic Variants in ASNA1, Encoding a Cytosolic Targeting Factor of Tail-Anchored Proteins, Cause Rapidly Progressive Pediatric Cardiomyopathy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 12:397-406. [PMID: 31461301 PMCID: PMC7205403 DOI: 10.1161/circgen.119.002507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Pediatric cardiomyopathies are a clinically and genetically heterogeneous group of heart muscle disorders associated with high morbidity and mortality. Although knowledge of the genetic basis of pediatric cardiomyopathy has improved considerably, the underlying cause remains elusive in a substantial proportion of cases.
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Affiliation(s)
- Judith M A Verhagen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Myrthe van den Born
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Herma C van der Linde
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Peter G J Nikkels
- Department of Pathology (P.G.J.N.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Rob M Verdijk
- Department of Pathology (R.M.V.), Erasmus MC, University Medical Center Rotterdam
| | - Maryann H Kivlen
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Leontine M A van Unen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Annette F Baas
- Department of Genetics (A.F.B.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Henriette Ter Heide
- Department of Pediatric Cardiology (H.t.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Lennie van Osch-Gevers
- Department of Pediatric Cardiology (L.v.O.-G.), Erasmus MC, University Medical Center Rotterdam
| | - Marianne Hoogeveen-Westerveld
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Johanna C Herkert
- Department of Genetics, University of Groningen, University Medical Center Groningen, the Netherlands (J.C.H.)
| | | | - Marjon A van Slegtenhorst
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Marja W Wessels
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Frans W Verheijen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - David Hassel
- Department of Medicine III, University Hospital Heidelberg, Germany (D.H.)
| | - Robert M W Hofstra
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Peter M van Hasselt
- Department of Pediatrics (P.M.v.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
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22
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Abstract
Introduction Phospholamban cardiomyopathy is an inherited cardiomyopathy, characterised by a defect in regulation of the sarcoplasmic reticulum Ca2+ pump, often presenting with malignant arrhythmias and progressive cardiac dysfunction occurring at a young age. Methods Phospholamban R14del mutation carriers and family members were identified from inherited arrhythmia clinics at 13 sites across Canada. Cardiac investigations, including electrocardiograms, Holter monitoring (premature ventricular complexes, PVCs), and imaging results were summarised. Results Fifty patients (10 families) were identified (median age 30 years, range 3–71, 46% female). Mutation carriers were more likely to be older, have low-voltage QRS, T‑wave inversion, frequent PVCs, and cardiac dysfunction, compared to unaffected relatives. Increasing age, low-voltage QRS, T‑wave inversion, late potentials, and frequent PVCs were predictors of cardiac dysfunction (p < 0.05 for all). Older carriers (age ≥45 years) were more likely to have disease manifestations than were their younger counterparts, with disease onset occurring at an older age in Canadian patients and their Dutch counterparts. Discussion Among Canadian patients with phospholamban cardiomyopathy, clinical manifestations resembled those of their Dutch counterparts, with increasing age a major predictor of disease manifestation. Older mutation carriers were more likely to have electrical and structural abnormalities, and may represent variable expressivity, age-dependent penetrance, or genetic heterogeneity among Canadian patients. Electronic supplementary material The online version of this article (10.1007/s12471-019-1247-0) contains supplementary material, which is available to authorized users.
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23
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Hof IE, van der Heijden JF, Kranias EG, Sanoudou D, de Boer RA, van Tintelen JP, van der Zwaag PA, Doevendans PA. Prevalence and cardiac phenotype of patients with a phospholamban mutation. Neth Heart J 2018; 27:64-69. [PMID: 30547415 PMCID: PMC6352623 DOI: 10.1007/s12471-018-1211-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Pathogenic mutations in the phospholamban (PLN) gene may give rise to inherited cardiomyopathies due to its role in calcium homeostasis. Several PLN mutations have been identified, with the R14del mutation being the most prevalent cardiomyopathy-related mutation in the Netherlands. It is present in patients diagnosed with arrhythmogenic cardiomyopathy as well as dilated cardiomyopathy. Awareness of the phenotype of this PLN mutation is of great importance, since many carriers remain to be identified. Patients with the R14del mutation are characterised by older age at onset, low-voltage electrocardiograms and a high frequency of ventricular arrhythmias. Additionally, these patients have a poor prognosis often with left ventricular dysfunction and early-onset heart failure. Therefore, when there is a suspicion of a PLN mutation, cardiac and genetic screening is strongly recommended.
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Affiliation(s)
- I E Hof
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - J F van der Heijden
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - E G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - D Sanoudou
- Department of Molecular Biology, Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - R A de Boer
- Department of Cardiology, University Medical Center Groningen, Groningen, The Netherlands
| | - J P van Tintelen
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - P A van der Zwaag
- Department of Clinical Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | - P A Doevendans
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Cardiology, Central Military Hospital, Utrecht, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
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24
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Chen M, Xu D, Wu AZ, Kranias E, Lin SF, Chen PS, Chen Z. Phospholamban regulates nuclear Ca 2+ stores and inositol 1,4,5-trisphosphate mediated nuclear Ca 2+ cycling in cardiomyocytes. J Mol Cell Cardiol 2018; 123:185-197. [PMID: 30261161 DOI: 10.1016/j.yjmcc.2018.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/04/2018] [Accepted: 09/21/2018] [Indexed: 01/15/2023]
Abstract
AIMS Phospholamban (PLB) is the key regulator of the cardiac Ca2+ pump (SERCA2a)-mediated sarcoplasmic reticulum Ca2+ stores. We recently reported that PLB is highly concentrated in the nuclear envelope (NE) from where it can modulate perinuclear Ca2+ handling of the cardiomyocytes (CMs). Since inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) mediates nuclear Ca2+ release, we examined whether the nuclear pool of PLB regulates IP3-induced nuclear Ca2+ handling. METHODS AND RESULTS Fluo-4 based confocal Ca2+ imaging was performed to measure Ca2+ dynamics across both nucleus and cytosol in saponin-permeabilized CMs isolated from wild-type (WT) or PLB-knockout (PLB-KO) mice. At diastolic intracellular Ca2+ ([Ca2+]i = 100 nM), the Fab fragment of the monoclonal PLB antibody (anti-PLB Fab) facilitated the formation and increased the length of spontaneous Ca2+ waves (SCWs) originating from the nuclear region in CMs from WT but not from PLB-KO mice. We next examined nuclear Ca2+ activities at basal condition and after sequential addition of IP3, anti-PLB Fab, and the IP3R inhibitor 2-aminoethoxydiphenyl borate (2-APB) at a series of [Ca2+]i. In WT mice, at 10 nM [Ca2+]i where ryanodine receptor (RyR2) based spontaneous Ca2+ sparks rarely occurred, IP3 increased fluorescence amplitude (F/F0) of overall nuclear region to 1.19 ± 0.02. Subsequent addition of anti-PLB Fab significantly decreased F/F0 to 1.09 ± 0.02. At 50 nM [Ca2+]i, anti-PLB Fab not only decreased the overall nuclear F/F0 previously elevated by IP3, but also increased the amplitude and duration of spark-like nuclear Ca2+ release events. These nuclear Ca2+ releases were blocked by 2-APB. At 100 nM [Ca2+]i, IP3 induced short SCWs originating from nucleus. Anti-PLB Fab transformed those short waves into long SCWs with propagation from the nucleus into the cytosol. In contrast, neither nuclear nor cytosolic Ca2+ dynamics was affected by anti-PLB Fab in CMs from PLB-KO mice in all these conditions. Furthermore, in WT CMs pretreated with RyR2 blocker tetracaine, IP3 and anti-PLB Fab still increased the magnitude of nuclear Ca2+ release but failed to regenerate SCWs. Finally, anti-PLB Fab increased low Ca2+ affinity mag-fluo 4 fluorescence intensity in the lumen of NE of nuclei isolated from WT but not in PLB-KO mice. CONCLUSION PLB regulates nuclear Ca2+ handling. By increasing Ca2+ uptake into lumen of the NE and perhaps other perinuclear membranes, the acute reversal of PLB inhibition decreases global Ca2+ concentration at rest in the nucleoplasm, and increases Ca2+ release into the nucleus, through mechanisms involving IP3R and RyR2 in the vicinity.
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Affiliation(s)
- Mu Chen
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA; Department of Cardiology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Dongzhu Xu
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA; Cardiovascular Division, Institute of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Japan
| | - Adonis Z Wu
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA
| | - Evangelia Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Shien-Fong Lin
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA; Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsin-Chu, Taiwan
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA
| | - Zhenhui Chen
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA.
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25
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Ion channels as part of macromolecular multiprotein complexes : Clinical significance. Herzschrittmacherther Elektrophysiol 2017; 29:30-35. [PMID: 29214349 PMCID: PMC5846830 DOI: 10.1007/s00399-017-0542-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022]
Abstract
Ion channels and Ca2+-handling proteins involved in the regulation of cardiac electrophysiology and contractility are organized in macromolecular multiprotein complexes. Recent molecular and cellular studies have significantly enhanced our understanding of the composition of these macromolecular complexes and have helped to elucidate their role in the dynamic regulation of ion channel function. Moreover, it has become clear that alterations in the composition of ion channel macromolecular complexes, for example, due to genetic mutations or acquired alterations in the expression of individual components, may lead to ion channel dysfunction and arrhythmogenesis. Here, we review novel insights into the composition of the major ion channel macromolecular complexes and discuss the potential clinical significance of alterations in these dynamic multiprotein structures.
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Ehsan M, Jiang H, L Thomson K, Gehmlich K. When signalling goes wrong: pathogenic variants in structural and signalling proteins causing cardiomyopathies. J Muscle Res Cell Motil 2017; 38:303-316. [PMID: 29119312 PMCID: PMC5742121 DOI: 10.1007/s10974-017-9487-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
Abstract
Cardiomyopathies are a diverse group of cardiac disorders with distinct phenotypes, depending on the proteins and pathways affected. A substantial proportion of cardiomyopathies are inherited and those will be the focus of this review article. With the wide application of high-throughput sequencing in the practice of clinical genetics, the roles of novel genes in cardiomyopathies are recognised. Here, we focus on a subgroup of cardiomyopathy genes [TTN, FHL1, CSRP3, FLNC and PLN, coding for Titin, Four and a Half LIM domain 1, Muscle LIM Protein, Filamin C and Phospholamban, respectively], which, despite their diverse biological functions, all have important signalling functions in the heart, suggesting that disturbances in signalling networks can contribute to cardiomyopathies.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Kate L Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK.
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van Opbergen CJM, Delmar M, van Veen TAB. Potential new mechanisms of pro-arrhythmia in arrhythmogenic cardiomyopathy: focus on calcium sensitive pathways. Neth Heart J 2017; 25:157-169. [PMID: 28102477 PMCID: PMC5313453 DOI: 10.1007/s12471-017-0946-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Arrhythmogenic cardiomyopathy, or its most well-known subform arrhythmogenic right ventricular cardiomyopathy (ARVC), is a cardiac disease mainly characterised by a gradual replacement of the myocardial mass by fibrous and fatty tissue, leading to dilatation of the ventricular wall, arrhythmias and progression towards heart failure. ARVC is commonly regarded as a disease of the intercalated disk in which mutations in desmosomal proteins are an important causative factor. Interestingly, the Dutch founder mutation PLN R14Del has been identified to play an additional, and major, role in ARVC patients within the Netherlands. This is remarkable since the phospholamban (PLN) protein plays a leading role in regulation of the sarcoplasmic reticulum calcium load rather than in the establishment of intercellular integrity. In this review we outline the intracellular cardiac calcium dynamics and relate pathophysiological signalling, induced by disturbed calcium handling, with activation of calmodulin dependent kinase II (CaMKII) and calcineurin A (CnA). We postulate a thus far unrecognised role for Ca2+ sensitive signalling proteins in maladaptive remodelling of the macromolecular protein complex that forms the intercalated disk, during pro-arrhythmic remodelling of the heart.
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Affiliation(s)
- C J M van Opbergen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, USA
| | - T A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
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Structure-Function Relationship of the SERCA Pump and Its Regulation by Phospholamban and Sarcolipin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:77-119. [DOI: 10.1007/978-3-319-55858-5_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Phospholamban is concentrated in the nuclear envelope of cardiomyocytes and involved in perinuclear/nuclear calcium handling. J Mol Cell Cardiol 2016; 100:1-8. [PMID: 27642167 DOI: 10.1016/j.yjmcc.2016.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/26/2016] [Accepted: 09/13/2016] [Indexed: 11/20/2022]
Abstract
AIMS Phospholamban (PLB) regulates the cardiac Ca2+-ATPase (SERCA2a) in sarcoplasmic reticulum (SR). However, the localization of PLB at subcellular sites outside the SR and possible contributions to Ca2+ cycling remain unknown. We examined the intracellular distribution of PLB and tested whether a pool of PLB exists in the nuclear envelope (NE) that might regulate perinuclear/nuclear Ca2+ (nCa2+) handling in cardiomyocytes (CMs). METHODS AND RESULTS Using confocal immunofluorescence microscopy and immunoblot analyses of CMs and CM nuclei, we discovered that PLB was highly concentrated in NE. Moreover, the ratio of PLB levels to SERCA levels was greater in NE than in SR. The increased levels of PLB in NE were a consistent finding using a range of antibodies, tissue samples, and species. To address a possible role in affecting Ca2+ handling, we used Fluo-4 based confocal Ca2+ imaging, with scan-lines across cytosol and nuclei, and evaluated the effects of PLB on cytosolic and nCa2+ uptake and release in mouse CMs. In intact CMs, isoproterenol increased amplitude and decreased the decay time of Ca2+ transients not only in cytosol but also in nuclear regions. In saponin-permeabilized mouse CMs ([Ca2+]i=400nM), we measured spontaneous Ca2+ waves after specific reversal of PLB activity by addition of the Fab fragment of an anti-PLB monoclonal antibody (100μg/ml). This highly selective immunological reagent enhanced Ca2+ uptake (faster decay times) and Ca2+ release (greater intensity) in both cytosol and across the nuclear regions. CONCLUSIONS Besides SR, PLB is concentrated in NE of CMs, and may be involved in modulation of nCa2+ dynamics.
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Te Rijdt WP, van Tintelen JP, Vink A, van der Wal AC, de Boer RA, van den Berg MP, Suurmeijer AJH. Phospholamban p.Arg14del cardiomyopathy is characterized by phospholamban aggregates, aggresomes, and autophagic degradation. Histopathology 2016; 69:542-50. [PMID: 26970417 DOI: 10.1111/his.12963] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 03/07/2016] [Indexed: 01/25/2023]
Abstract
AIMS The non-desmosomal phospholamban PLN p.Arg14del mutation was identified in patients diagnosed with dilated cardiomyopathy (DCM) and/or arrhythmogenic cardiomyopathy (ACM). We aimed to investigate whether this mutation leads to aggregation, aggresome formation and autophagy of mutant PLN protein. METHODS AND RESULTS We studied 20 complete heart specimens of PLN p.Arg14del mutation carriers [mean age 48 ± 15 years; 55% males], either from autopsies or from explants. Gross and microscopic examination showed biventricular cardiomyopathy with histopathological features of both ACM and DCM, i.e. a combination of fibrofatty replacement and interstitial fibrosis. Immunohistochemistry for PLN showed large perinuclear PLN protein aggregates in cardiomyocytes in both ventricles in all examined hearts. The median numbers of PLN-containing aggregates were 12 per 5 mm(2) range 3-48 mm2 in right ventricular myocardium and 13 per 5 mm(2) (range 5-89 mm(2) ) in left ventricular myocardium. Double immunohistochemical staining showed colocalization of autophagy markers p62 (sequestosome-1) and microtubule-associated protein light chain 3 with PLN in all aggregates, suggestive of degradation by selective autophagy. On electron microscopy, the ultrastructural appearance of these PLN-containing aggregates was typical of aggresomes; they were not surrounded by a membrane, and were located adjacent to the microtubular organizing centre. PLN-containing aggregates were not found in 10 PLN-negative cases of idiopathic and genetic DCM or in seven cases of desmosomal ACM. CONCLUSIONS PLN p.Arg14del cardiomyopathy is a biventricular cardiomyopathy characterized by large perinuclear PLN protein aggregates with a typical ultrastructural appearance of aggresomes. PLN detected by immunohistochemistry appears to be a sensitive and specific marker for this disease.
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Affiliation(s)
- Wouter P Te Rijdt
- Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.,Department of Pathology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.,Interuniversity Cardiology Institute of The Netherlands (ICIN), Utrecht, the Netherlands
| | - J Peter van Tintelen
- Department of Clinical Genetics, University of Amsterdam, Academic Medical Centre, Amsterdam, the Netherlands
| | - Aryan Vink
- Department of Pathology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Allard C van der Wal
- Department of Pathology, University of Amsterdam, Academic Medical Centre, Amsterdam, the Netherlands
| | - Rudolf A de Boer
- Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Maarten P van den Berg
- Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Albert J H Suurmeijer
- Department of Pathology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.
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Lee JD, Yang WK, Lee MH. Impaired Na(+)/K(+)-ATPase Function in Patients with Interstitial Cystitis/Painful Bladder Syndrome. J Korean Med Sci 2016; 31:280-5. [PMID: 26839484 PMCID: PMC4729510 DOI: 10.3346/jkms.2016.31.2.280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/02/2015] [Indexed: 12/29/2022] Open
Abstract
Na(+)/K(+)-ATPase (NKA) is abundantly expressed in the basolateral membrane of epithelial cells, which is necessary for tight junction formation. The tight junction is an urothelial barrier between urine and the underlying bladder. Impairment of tight junctions allows migration of urinary solutes in patients with interstitial cystitis/painful bladder syndrome (IC/PBS). We evaluated NKA expression and activity in bladder samples from patients with IC/PBS. The study group consisted of 85 patients with IC/PBS, and the control group consisted of 20 volunteers. Bladder biopsies were taken from both groups. We determined the expression and distribution of NKA using NKA activity assays, immunoblotting, immunohistochemical staining, and immunofluorescent staining. The protein levels and activity of NKA in the study group were significantly lower than the control group (1.08 ± 0.06 vs. 2.39 ± 0.29 and 0.60 ± 0.04 vs. 1.81 ± 0.18 µmol ADP/mg protein/hour, respectively; P < 0.05). Additionally, immunofluorescent staining for detection of CK7, a marker of the bladder urothelium, predominantly colocalized with NKA in patients in the study group. Our results demonstrated the expression and activity of NKA were decreased in bladder biopsies of patients with IC/PBS. These findings suggest that NKA function is impaired in the bladders from patients with IC/PBS.
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Affiliation(s)
- Jane-Dar Lee
- Division of Urology, Department of Surgery, Taichung Armed Forces General Hospital, Taichung, Taiwan, Republic of China
- Central Taiwan University of Science and Technology, Taichung, Taiwan, Republic of China
- National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Wen-Kai Yang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Ming-Huei Lee
- Department of Urology, Feng-Yuan Hospital, Ministry of Health and Welfare, Taichung, Taiwan, Republic of China
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Abstract
The various isoforms of the sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) are responsible for the Ca(2+) uptake from the cytosol into the endoplasmic or sarcoplasmic reticulum (ER/SR). In some tissues, the activity of SERCA can be modulated by binding partners, such as phospholamban and sarcolipin. The activity of SERCA can be characterized by its apparent affinity for Ca(2+) as well as maximal enzymatic velocity. Both parameters can be effectively determined by the protocol described here. Specifically, we describe the measurement of the rate of oxalate-facilitated (45)Ca uptake into the SR of crude mouse ventricular homogenates. This protocol can easily be adapted for different tissues and animal models as well as cultured cells.
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Affiliation(s)
- Philip A Bidwell
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA.
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Rigatti M, Le AV, Gerber C, Moraru II, Dodge-Kafka KL. Phosphorylation state-dependent interaction between AKAP7δ/γ and phospholamban increases phospholamban phosphorylation. Cell Signal 2015; 27:1807-15. [PMID: 26027516 DOI: 10.1016/j.cellsig.2015.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/07/2015] [Indexed: 12/01/2022]
Abstract
Changes in heart rate and contractility in response to sympathetic stimulation occur via activation of cAMP dependent protein kinase A (PKA), leading to phosphorylation of numerous substrates that alter Ca(2+) cycling. Phosphorylation of these substrates is coordinated by A-kinase anchoring proteins (AKAPs), which recruit PKA to specific substrates [1]. Phosphorylation of the PKA substrate phospholamban (PLB) is a critical determinant of Ca(2+) re-entry into the sarcoplasmic reticulum and is coordinated by AKAP7δ/γ [2,3]. Here, we further these findings by showing that phosphorylation of PLB requires interaction with AKAP7δ/γ and that this interaction occurs only when PLB is unphosphorylated. Additionally, we find that two mutants of PLB (R9C and Δ14), which are associated with dilated cardiomyopathy in humans, prevent association with AKAP7δ/γ and display reduced phosphorylation in vitro. This finding implicates the AKAP7δ/γ-PLB interaction in the pathology of the disease phenotype. Further exploration of the AKAP7δ/γ-PLB association demonstrated a phosphorylation state-dependence of the interaction. Computational modeling revealed that this mode of interaction allows for small amounts of AKAP and PKA (100-200nM) to regulate the phosphorylation of large quantities of PLB (50μM). Our results confirm that AKAP7γ/δ binding to PLB is important for phosphorylation of PLB, and describe a novel phosphorylation state-dependent binding mechanism that explains how phosphorylation of highly abundant PKA substrates can be regulated by AKAPs present at ~100-200 fold lower concentrations.
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Affiliation(s)
- Marc Rigatti
- Pat and Jim Calhoun Center for Cardiovascular Research, UCONN Health, 263 Farmington Ave, Farmington, CT 06030, USA; The Richard D. Berlin Center for Cell Analysis & Modeling, UCONN Health, 400 Farmington Ave, Farmington, CT 06030, USA
| | - Andrew V Le
- Pat and Jim Calhoun Center for Cardiovascular Research, UCONN Health, 263 Farmington Ave, Farmington, CT 06030, USA; The Richard D. Berlin Center for Cell Analysis & Modeling, UCONN Health, 400 Farmington Ave, Farmington, CT 06030, USA
| | - Claire Gerber
- Pat and Jim Calhoun Center for Cardiovascular Research, UCONN Health, 263 Farmington Ave, Farmington, CT 06030, USA; The Richard D. Berlin Center for Cell Analysis & Modeling, UCONN Health, 400 Farmington Ave, Farmington, CT 06030, USA
| | - Ion I Moraru
- Pat and Jim Calhoun Center for Cardiovascular Research, UCONN Health, 263 Farmington Ave, Farmington, CT 06030, USA; The Richard D. Berlin Center for Cell Analysis & Modeling, UCONN Health, 400 Farmington Ave, Farmington, CT 06030, USA
| | - Kimberly L Dodge-Kafka
- Pat and Jim Calhoun Center for Cardiovascular Research, UCONN Health, 263 Farmington Ave, Farmington, CT 06030, USA; The Richard D. Berlin Center for Cell Analysis & Modeling, UCONN Health, 400 Farmington Ave, Farmington, CT 06030, USA.
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Correction of human phospholamban R14del mutation associated with cardiomyopathy using targeted nucleases and combination therapy. Nat Commun 2015; 6:6955. [PMID: 25923014 PMCID: PMC4421839 DOI: 10.1038/ncomms7955] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 03/18/2015] [Indexed: 12/19/2022] Open
Abstract
A number of genetic mutations is associated with cardiomyopathies. A mutation in the coding region of the phospholamban (PLN) gene (R14del) is identified in families with hereditary heart failure. Heterozygous patients exhibit left ventricular dilation and ventricular arrhythmias. Here we generate induced pluripotent stem cells (iPSCs) from a patient harbouring the PLN R14del mutation and differentiate them into cardiomyocytes (iPSC-CMs). We find that the PLN R14del mutation induces Ca2+ handling abnormalities, electrical instability, abnormal cytoplasmic distribution of PLN protein and increases expression of molecular markers of cardiac hypertrophy in iPSC-CMs. Gene correction using transcription activator-like effector nucleases (TALENs) ameliorates the R14del-associated disease phenotypes in iPSC-CMs. In addition, we show that knocking down the endogenous PLN and simultaneously expressing a codon-optimized PLN gene reverses the disease phenotype in vitro. Our findings offer novel strategies for targeting the pathogenic mutations associated with cardiomyopathies. Phospholamban (PLN) is a regulator of heart contractility. Here the authors show that cardiomyocytes derived from induced pluripotent stem cells of a cardiomyopathy patient with mutant PLN exhibit functional defects consistent with the disease, and that this mutation can be functionally corrected by genome editing and gene therapy.
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35
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Dasgupta T, Coram RJ, Stillwagon SJ, Ladd AN. Gene Expression Analyses during Spontaneous Reversal of Cardiomyopathy in Mice with Repressed Nuclear CUG-BP, Elav-Like Family (CELF) Activity in Heart Muscle. PLoS One 2015; 10:e0124462. [PMID: 25894229 PMCID: PMC4404138 DOI: 10.1371/journal.pone.0124462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/03/2015] [Indexed: 01/05/2023] Open
Abstract
CUG-BP, Elav-like family (CELF) proteins regulate cell type- and developmental stage-specific alternative splicing in the heart. Repression of CELF-mediated splicing activity via expression of a nuclear dominant negative CELF protein in heart muscle was previously shown to induce dysregulation of alternative splicing, cardiac dysfunction, cardiac hypertrophy, and dilated cardiomyopathy in MHC-CELFΔ transgenic mice. A “mild” line of MHC-CELFΔ mice that expresses a lower level of the dominant negative protein exhibits cardiac dysfunction and myopathy at a young age, but spontaneously recovers normal cardiac function and heart size with age despite the persistence of splicing defects. To the best of our knowledge, this was the first example of a genetically induced cardiomyopathy that spontaneously recovers without intervention. In this study, we explored the basis for this recovery. We examined whether a transcriptional program regulated by serum response factor (SRF) that is dysregulated in juvenile MHC-CELFΔ mice is restored in the mild line with age, and evaluated global changes in gene expression by microarray analyses. We found that differences in gene expression between the mild line and wild type hearts are greatly reduced in older animals, including a partial recovery of SRF target gene expression. We did not find evidence of a new compensatory pathway being activated in the mild line with age, and propose that recovery may occur due to developmental stage-specific compatibility of CELF-dependent splice variants with the cellular environment of the cardiomyocyte.
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Affiliation(s)
- Twishasri Dasgupta
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Ryan J. Coram
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Samantha J. Stillwagon
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Andrea N. Ladd
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
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36
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Dysfunctional conformational dynamics of protein kinase A induced by a lethal mutant of phospholamban hinder phosphorylation. Proc Natl Acad Sci U S A 2015; 112:3716-21. [PMID: 25775607 DOI: 10.1073/pnas.1502299112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamic interplay between kinases and substrates is crucial for the formation of catalytically committed complexes that enable phosphoryl transfer. However, a clear understanding on how substrates modulate kinase structural dynamics to control catalytic efficiency is still missing. Here, we used solution NMR spectroscopy to study the conformational dynamics of two complexes of the catalytic subunit of the cAMP-dependent protein kinase A with WT and R14 deletion phospholamban, a lethal human mutant linked to familial dilated cardiomyopathy. Phospholamban is a central regulator of heart muscle contractility, and its phosphorylation by protein kinase A constitutes a primary response to β-adrenergic stimulation. We found that the single deletion of arginine in phospholamban's recognition sequence for the kinase reduces its binding affinity and dramatically reduces phosphorylation kinetics. Structurally, the mutant prevents the enzyme from adopting conformations and motions committed for catalysis, with concomitant reduction in catalytic efficiency. Overall, these results underscore the importance of a well-tuned structural and dynamic interplay between the kinase and its substrates to achieve physiological phosphorylation levels for proper Ca(2+) signaling and normal cardiac function.
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Ablorh NAD, Thomas DD. Phospholamban phosphorylation, mutation, and structural dynamics: a biophysical approach to understanding and treating cardiomyopathy. Biophys Rev 2015; 7:63-76. [PMID: 28509982 DOI: 10.1007/s12551-014-0157-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/26/2014] [Indexed: 01/16/2023] Open
Abstract
We review the recent development of novel biochemical and spectroscopic methods to determine the site-specific phosphorylation, expression, mutation, and structural dynamics of phospholamban (PLB), in relation to its function (inhibition of the cardiac calcium pump, SERCA2a), with specific focus on cardiac physiology, pathology, and therapy. In the cardiomyocyte, SERCA2a actively transports Ca2+ into the sarcoplasmic reticulum (SR) during relaxation (diastole) to create the concentration gradient that drives the passive efflux of Ca2+ required for cardiac contraction (systole). Unphosphorylated PLB (U-PLB) inhibits SERCA2a, but phosphorylation at S16 and/or T17 (producing P-PLB) changes the structure of PLB to relieve SERCA2a inhibition. Because insufficient SERCA2a activity is a hallmark of heart failure, SERCA2a activation, by gene therapy (Andino et al. 2008; Fish et al. 2013; Hoshijima et al. 2002; Jessup et al. 2011) or drug therapy (Ferrandi et al. 2013; Huang 2013; Khan et al. 2009; Rocchetti et al. 2008; Zhang et al. 2012), is a widely sought goal for treatment of heart failure. This review describes rational approaches to this goal. Novel biophysical assays, using site-directed labeling and high-resolution spectroscopy, have been developed to resolve the structural states of SERCA2a-PLB complexes in vitro and in living cells. Novel biochemical assays, using synthetic standards and multidimensional immunofluorescence, have been developed to quantitate PLB expression and phosphorylation states in cells and human tissues. The biochemical and biophysical properties of U-PLB, P-PLB, and mutant PLB will ultimately resolve the mechanisms of loss of inhibition and gain of inhibition to guide therapeutic development. These assays will be powerful tools for investigating human tissue samples from the Sydney Heart Bank, for the purpose of analyzing and diagnosing specific disorders.
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Affiliation(s)
- Naa-Adjeley D Ablorh
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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Haghighi K, Bidwell P, Kranias EG. Phospholamban interactome in cardiac contractility and survival: A new vision of an old friend. J Mol Cell Cardiol 2014; 77:160-7. [PMID: 25451386 PMCID: PMC4312245 DOI: 10.1016/j.yjmcc.2014.10.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/06/2014] [Accepted: 10/09/2014] [Indexed: 01/10/2023]
Abstract
Depressed sarcoplasmic reticulum (SR) calcium cycling, reflecting impaired SR Ca-transport and Ca-release, is a key and universal characteristic of human and experimental heart failure. These SR processes are regulated by multimeric protein complexes, including protein kinases and phosphatases as well as their anchoring and regulatory subunits that fine-tune Ca-handling in specific SR sub-compartments. SR Ca-transport is mediated by the SR Ca-ATPase (SERCA2a) and its regulatory phosphoprotein, phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA2a and phosphorylation by protein kinase A (PKA) or calcium-calmodulin-dependent protein kinases (CAMKII) relieves these inhibitory effects. Recent studies identified additional regulatory proteins, associated with PLN, that control SR Ca-transport. These include the inhibitor-1 (I-1) of protein phosphatase 1 (PP1), the small heat shock protein 20 (Hsp20) and the HS-1 associated protein X-1 (HAX1). In addition, the intra-luminal histidine-rich calcium binding protein (HRC) has been shown to interact with both SERCA2a and triadin. Notably, there is physical and direct interaction between these protein players, mediating a fine-cross talk between SR Ca-uptake, storage and release. Importantly, regulation of SR Ca-cycling by the PLN/SERCA interactome does not only impact cardiomyocyte contractility, but also survival and remodeling. Indeed, naturally occurring variants in these Ca-cycling genes modulate their activity and interactions with other protein partners, resulting in depressed contractility and accelerated remodeling. These genetic variants may serve as potential prognostic or diagnostic markers in cardiac pathophysiology.
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Affiliation(s)
- Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Philip Bidwell
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA.
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Lymperopoulos A, Garcia D, Walklett K. Pharmacogenetics of cardiac inotropy. Pharmacogenomics 2014; 15:1807-1821. [PMID: 25493572 DOI: 10.2217/pgs.14.120] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The ability to stimulate cardiac contractility is known as positive inotropy. Endogenous hormones, such as adrenaline and several natural or synthetic compounds possess this biological property, which is invaluable in the modern cardiovascular therapy setting, especially in acute heart failure or in cardiogenic shock. A number of proteins inside the cardiac myocyte participate in the molecular pathways that translate the initial stimulus, that is, the hormone or drug, into the effect of increased contractility (positive inotropy). Genetic variations (polymorphisms) in several genes encoding these proteins have been identified and characterized in humans with potentially significant consequences on cardiac inotropic function. The present review discusses these polymorphisms and their effects on cardiac inotropy, along with the individual pharmacogenomics of the most important positive inotropic agents in clinical use today. Important areas for future investigations in the field are also highlighted.
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Affiliation(s)
- Anastasios Lymperopoulos
- From the Laboratory for the Study of Neurohormonal Control of the Circulation, Department of Pharmaceutical Sciences, Nova Southeastern University College of Pharmacy, 3200 S. University Drive, HPD (Terry) Bldg/Room 1338, Ft. Lauderdale, FL 33328-2018, USA
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Abstract
Recent advances in our understanding of the pathophysiology of myocardial dysfunction in the setting of congestive heart failure have created a new opportunity in developing nonpharmacological approaches to treatment. Gene therapy has emerged as a powerful tool in targeting the molecular mechanisms of disease by preventing the ventricular remodeling and improving bioenergetics in heart failure. Refinements in vector technology, including the creation of recombinant adeno-associated viruses, have allowed for safe and efficient gene transfer. These advancements have been coupled with evolving delivery methods that include vascular, pericardial, and direct myocardial approaches. One of the most promising targets, SERCA2a, is currently being used in clinical trials. The recent success of the Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease phase 2 trials using adeno-associated virus 1-SERCA2a in improving outcomes highlights the importance of gene therapy as a future tool in treating congestive heart failure.
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41
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Vostrikov VV, Soller KJ, Ha KN, Gopinath T, Veglia G. Effects of naturally occurring arginine 14 deletion on phospholamban conformational dynamics and membrane interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:315-22. [PMID: 25251363 DOI: 10.1016/j.bbamem.2014.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/12/2014] [Accepted: 09/13/2014] [Indexed: 01/10/2023]
Abstract
Phospholamban (PLN) is a single-pass membrane protein that regulates the sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA). Phosphorylation of PLN at Ser16 reverses its inhibitory function under β-adrenergic stimulation, augmenting Ca²⁺ uptake in the sarcoplasmic reticulum and muscle contractility. PLN exists in two conformations; a T state, where the cytoplasmic domain is helical and adsorbed on the membrane surface, and an R state, where the cytoplasmic domain is unfolded and membrane detached. Previous studies have shown that the PLN conformational equilibrium is crucial to SERCA regulation. Here, we used a combination of solution and solid-state NMR to compare the structural topology and conformational dynamics of monomeric PLN (PLN(AFA)) with that of the PLN(R14del), a naturally occurring deletion mutant that is linked to the progression of dilated cardiomyopathy. We found that the behavior of the inhibitory transmembrane domain of PLN(R14del) is similar to that of the native sequence. Conversely, the conformational dynamics of R14del both in micelles and lipid membranes are enhanced. We conclude that the deletion of Arg14 in the cytoplasmic region weakens the interactions with the membrane and shifts the conformational equilibrium of PLN toward the disordered R state. This conformational transition is correlated with the loss-of-function character of this mutant and is corroborated by SERCA's activity assays. These findings support our hypothesis that SERCA function is fine-tuned by PLN conformational dynamics and begin to explain the aberrant regulation of SERCA by the R14del mutant.
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Affiliation(s)
- Vitaly V Vostrikov
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kailey J Soller
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kim N Ha
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Chemistry and Biochemistry, St. Catherine University, St. Paul, MN 55105, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
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Hughes E, Middleton DA. Comparison of the structure and function of phospholamban and the arginine-14 deficient mutant associated with dilated cardiomyopathy. PLoS One 2014; 9:e106746. [PMID: 25225809 PMCID: PMC4165587 DOI: 10.1371/journal.pone.0106746] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/01/2014] [Indexed: 12/20/2022] Open
Abstract
Phospholamban (PLB) is a pentameric protein that plays an important role in regulating cardiac contractility via a reversible inhibitory association with the sarcoplasmic reticulum Ca2+ATPase (SERCA), the enzyme responsible for maintaining correct calcium homeostasis. Here we study the functional and biophysical characteristics of a PLB mutant associated with human dilated cardiomyopathy (DCM), with a deletion of arginine at position 14 (PLBR14Δ). In agreement with recent findings, we find that PLBR14Δ has a reduced inhibitory effect on SERCA compared to wild type PLB (PLBWT) when reconstituted into lipid membranes. The mutation also leads to a large reduction in the protein kinase A-catalysed phosphorylation of Ser-16 in the cytoplasmic domain of PLBR14Δ. Measurements on SERCA co-reconstituted with an equimolar mixture of PLBWT and PLBR14Δ (representing the lethal heterozygous state associated with DCM) indicates that the loss-of-function mutation has a dominant effect on PLBWT functionality and phosphorylation capacity, suggesting that mixed PLBWT/PLBR14Δ pentamers are formed that have characteristics typical of the mutant protein. Structural and biophysical analysis of PLBR14Δ indicates that the mutation perturbs slightly the helical structure of the PLB cytoplasmic domain and reduces its affinity for the phospholipid bilayer surface, thereby altering the orientation of the cytoplasmic domain relative to the wild-type protein. These results indicate that the structure and function consequences of the R14 deletion have profound effects on the regulation of SERCA which may contribute to the aetiology of DCM.
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Affiliation(s)
- Eleri Hughes
- Department of Chemistry, Lancaster University, Lancaster, United Kingdom
| | - David A Middleton
- Department of Chemistry, Lancaster University, Lancaster, United Kingdom
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Abstract
Ca²⁺ plays a crucial role in connecting membrane excitability with contraction in myocardium. The hallmark features of heart failure are mechanical dysfunction and arrhythmias; defective intracellular Ca²⁺ homeostasis is a central cause of contractile dysfunction and arrhythmias in failing myocardium. Defective Ca²⁺ homeostasis in heart failure can result from pathological alteration in the expression and activity of an increasingly understood collection of Ca²⁺ homeostatic and structural proteins, ion channels, and enzymes. This review focuses on the molecular mechanisms of defective Ca²⁺ cycling in heart failure and considers how fundamental understanding of these pathways may translate into novel and innovative therapies.
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Affiliation(s)
- Min Luo
- Division of Cardiovascular Medicine, Department of Internal Medicine, Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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Abstract
Heart disease remains the leading cause of death and disability in the Western world. Current therapies aim at treating the symptoms rather than the subcellular mechanisms, underlying the etiology and pathological remodeling in heart failure. A universal characteristic, contributing to the decreased contractile performance in human and experimental failing hearts, is impaired calcium sequestration into the sarcoplasmic reticulum (SR). SR calcium uptake is mediated by a Ca(2+)-ATPase (SERCA2), whose activity is reversibly regulated by phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA and phosphorylation of PLN relieves this inhibition. However, the initial simple view of a PLN/SERCA regulatory complex has been modified by our recent identification of SUMO, S100 and the histidine-rich Ca-binding protein as regulators of SERCA activity. In addition, PLN activity is regulated by 2 phosphoproteins, the inhibitor-1 of protein phosphatase 1 and the small heat shock protein 20, which affect the overall SERCA-mediated Ca-transport. This review will highlight the regulatory mechanisms of cardiac contractility by the multimeric SERCA/PLN-ensemble and the potential for new therapeutic avenues targeting this complex by using small molecules and gene transfer methods.
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Affiliation(s)
- Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0575, USA.
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Ceholski DK, Trieber CA, Holmes CFB, Young HS. Lethal, hereditary mutants of phospholamban elude phosphorylation by protein kinase A. J Biol Chem 2012; 287:26596-605. [PMID: 22707725 DOI: 10.1074/jbc.m112.382713] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The sarcoplasmic reticulum calcium pump (SERCA) and its regulator, phospholamban, are essential components of cardiac contractility. Phospholamban modulates contractility by inhibiting SERCA, and this process is dynamically regulated by β-adrenergic stimulation and phosphorylation of phospholamban. Herein we reveal mechanistic insight into how four hereditary mutants of phospholamban, Arg(9) to Cys, Arg(9) to Leu, Arg(9) to His, and Arg(14) deletion, alter regulation of SERCA. Deletion of Arg(14) disrupts the protein kinase A recognition motif, which abrogates phospholamban phosphorylation and results in constitutive SERCA inhibition. Mutation of Arg(9) causes more complex changes in function, where hydrophobic substitutions such as cysteine and leucine eliminate both SERCA inhibition and phospholamban phosphorylation, whereas an aromatic substitution such as histidine selectively disrupts phosphorylation. We demonstrate that the role of Arg(9) in phospholamban function is multifaceted: it is important for inhibition of SERCA, it increases the efficiency of phosphorylation, and it is critical for protein kinase A recognition in the context of the phospholamban pentamer. Given the synergistic consequences on contractility, it is not surprising that the mutants cause lethal, hereditary dilated cardiomyopathy.
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Affiliation(s)
- Delaine K Ceholski
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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